1. Field of the Invention
The present invention relates to a manufacturing method of a liquid jet head for discharging/flying droplets to deposit the droplets to a recording medium.
2. Description of the Related Art
A liquid jet head for use in a liquid jet recording system (ink jet print system) generally includes a discharge port (orifice) for discharging liquids such as ink, a liquid flow path connected to the discharge port, and a liquid discharge energy generation element disposed in the liquid flow path. The head has characteristics that generation of noises at a recording time is small to an ignorable degree, high-speed recording and recording with respect to various recording mediums are possible, the recording liquid is fixed even to a so-called plain paper without requiring any special treatment, and a high-precision image is inexpensively obtained. Because of these advantages, use of such a head has rapidly spread, not only in a printer which is a peripheral apparatus of a computer but also in a printing system such as a copying machine, facsimile, and word processor over the past several years. For liquid discharge methods of a liquid jet apparatus for broad and general use, there have been a method of using an electrothermal conversion device (heater), and a method of using a piezoelectric element (piezo element). In either method, it is possible to control the discharge of the droplets by an electric signal.
As a method of preparing this liquid jet head, for example, a method has been known in which, after forming a fine groove for forming a liquid flow path in a plate of glass or metal by a processing method such as cutting and etching, a substrate for the liquid jet head, including a liquid discharge energy generation element, is bonded to the plate in which the groove is formed to form a liquid flow path.
For example, as described in Japanese Patent Application Laid-Open No. 6-255099, a method is known in which a vibration plate including a diaphragm portion is laminated on the piezoelectric element as the liquid discharge energy generation element. A liquid chamber to be pressurized by the piezoelectric element through the diaphragm portion and a liquid flow path forming member for forming a liquid flow path to supply the liquid to the liquid chamber are laminated on the vibration plate. Furthermore, a nozzle forming member in which a nozzle hole is formed is laminated on the liquid flow path forming member.
Moreover, for example, Japanese Patent Application Laid-Open No. 6-115071 discloses a method in which a plurality of piezoelectric elements which are liquid discharge energy generation elements are bonded/arranged in a row onto the substrate. Furthermore, a liquid common channel member positioned around the piezoelectric elements to form a liquid common channel is bonded. The vibration plate is bonded onto the liquid common channel member, a partition wall member is bonded onto the vibration plate, a nozzle plate is bonded onto the partition wall member, and a liquid chamber (pressurized liquid chamber) to be pressurized through the vibration plate by the piezoelectric element is formed by the vibration plate, partition wall member, and nozzle plate.
Furthermore, for example, Japanese Patent Application Laid-Open No. 8-142324 discloses a method in which a plurality of piezoelectric elements are bonded in a plurality of rows onto the substrate, and a frame member positioned around the piezoelectric elements is also bonded so that an actuator unit is constituted. A liquid chamber partition wall member for forming a pressurized liquid chamber to be pressurized by the piezoelectric element through a diaphragm portion and a common liquid chamber to supply the liquid to this liquid chamber is laminated on a vibration plate which includes the diaphragm portion. Furthermore, a nozzle plate in which the nozzle is formed is laminated on the liquid chamber partition wall member to form a liquid chamber unit. The liquid chamber unit is bonded to the actuator unit.
Additionally, for example, as described in Japanese Patent Application Laid-Open No. 6-297704, a photosensitive resin is used as the liquid chamber partition wall member to bond a plurality of photosensitive resin layers so that the liquid chamber is formed. Alternatively, another resin molding is employed, or a multiplicity of layers of metal plates are bonded to one another so as to form a fine liquid chamber.
However, in the above-described conventional manufacturing method of the liquid jet head, when the groove forming the liquid flow path is formed by a cutting step, it is difficult to smoothen an inner wall surface of the groove. Moreover, the plate easily cracks or breaks, and the yield is not very good. On the other hand, when the groove is formed by etching, it is difficult to perform the etching uniformly with respect to all the grooves for forming the liquid flow paths. There are also disadvantages that the process is complicated and the manufacturing cost is increased. Accordingly, it is difficult to prepare the liquid jet heads uniformly including uniform liquid flow paths even by any processing means, and the obtained liquid jet heads tend to have unevenness in print characteristics. Furthermore, when bonding the plate, in which the groove for forming the liquid flow path is formed, to the substrate for the liquid jet head, in which the liquid discharge energy generation element is disposed, it has been difficult to position the groove and liquid discharge energy generation element with good precision. Therefore, the above-described conventional manufacturing method has not been suitable for mass production of high-quality liquid jet heads.
As described above, in the related art, various steps are carried out in the manufacturing method of the liquid jet head. However, in any step, it has been a problem to form a high-precision liquid flow path. Moreover, even if the high-precision liquid flow path can be formed, it has been a problem to exactly position the liquid flow path with respect to the liquid discharge energy generation element.